It is signed as a north–south highway, but occupies an L-shaped alignment running west, southwest, then north.

SR 230 begins at SR 3 in Trenton near Hancock County-Bar Harbor Airport, just north of the bridge approach to Mount Desert Island.

At Goose Cove Road, a bypass of the southernmost part of SR 230, the highway turns south towards Oak Point and the Mount Desert Narrows.

Approximately 0.6 miles (0.97 km) north of the shore's edge at Oak Point, SR 230 leaves Oak Point Road and makes a sharp turn directly north on Bayside Road.

The highway runs north along the Union River Bay, which transitions into the river proper as SR 230 crosses into the city of Ellsworth.